Fuel injector



H. F. HAINES FUEL INJECTOR- Filed Jul s, 1941 "Se t 19, 1944.

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Patented Sept. 19, 1944 FUEL nmzcron Harry F. Haines, Canton, Ohio, asslgnor to The Timkcn Roller Bearing Company, Canton, Ohio, a corporation of Ohio Application July 5, 1941 Serial No. 401,233 3 Claims. (of. 299-1071;)

This invention relates to fuel injectors forv compression ignition engines, and more particu larly to fuel injectors of the type having a springloaded valve that is opened hydraulically by the fuel pressure. The invention has for its principal object to improve the means for limiting the opening movement or lift of the valve and the means for transmitting the end thrust between the valve and valve spring. Other objects are simplicity, cheapness and durability of construction and compactness of design. The invention consists in the fuel injector and in the construction, combinations and arrangements of parts hereinafter described and claimed.

In the accompanying drawing, which forms part of this specification and wherein like symbols refer to like parts wherever they occur,

Fig. 1 is a central longitudinal section through a fuel injector embodying my invention; and Fig. 2 is an enlarged central longitudinal section through the injector in the region of the end thrust transmitting thimble.

In the accompanying drawing, my invention is shown embodied in a fuel injector for an internal combustion engine of the Diesel type. The injector comprises a nozzle holder A having a fuel inlet'or supply passageway I that leads inwardly through one side of said holder and thence downwardly through the lower end thereof. The cylindrical nozzle or jet element B of the injector is rigidly secured to the lower end of the holder A-by means of-a sleeve nut C that is threaded on said end and has an internal annular shoulder 2 adapted to bear against the external annular shoulder 3 on said nozzle and thus rigidly clamp the same in en'dwise abutting relation to the holder. The nozzle B has an axial bore 4 extendingtherethrough that is enlarged adjacent to its lower end to form a chamber '5; and

- communication is established between the fuel inlet or supply passageway I and said chamber through an annular groove 6 in the upper end of said nozzle and one or more passageways I leading from said groove to said chamber.

Reciprocable in the bore 4 of the nozzle B is a cylindrical plunger 8 which terminates at its lower end in a pin 8 that cooperates with the lower end of said bore to form an annular discharge orifice III. The plunger I is provided just above the pin 9 with an annular valve portion or element II adapted to cooperate with an annular valve seat I2 in the chamber and thus. prevent flow of fuel through the annular discharge orifice II. The plunger also has a conical portion is located in the chamber 5, whereby the plunger is adapted to be forced upwardly in the nozzle to lift the valve II off its seat by the hydraulic pressure of the fuel on said conical portion. The plunger 8 has its upper end reduced t form a stem portion I4 upon which is supp rted an end thrust member or thimble I5 located in the lower end portion of a bore I6 that extends through the holder A from top to bottom thereof in axial alinement with the axial bore of the nozzle-B. The thimble I5 seats on the upper end of the stem I4 of the plunger 8 with its lower end disposed clear of the annular shoulder I'I formed by said stem and enlarged to form an annularstop shoulder or collar I8; and the bore IS in the holder A is enlarged or counterbored, as at I9, where it opens through the nozzle receiving end of said holder, to provide an annular stop or abutment shoulder for the stop shoulder I8 of said thimble. The plunger 8 is snugly guided in the axial bore 4 of the nozzle B; and an annular clearance space is preferably provided between the thimble I5 and the bore I6 01' the nozzle holder A. The bore I G of the holder is enlarged near the upper end of the thimble I5 to receive a coil compression valve closing spring 20; and said thimble is provided near the upper end thereof with a slip or snap ring 2! adapted,

when the nozzle B is detached from said holder,.

to abut against the annular shoulder 22 formed by such enlargement and thus retain said thimble in said holder. The thrust member or thimble I5 has its upper end member reduced to form an annular shoulder or seat 23 for the lower end of the valve closing spring 20. The upper end of the spring receiving bore I6 is closed by a threaded plug 24, which forms a seat for the upper end of the valve spring 20; and this plug has an axial extending pin 25 depending therefrom which extends downwardly through the spring and serves as a guide therefor. Shims 26 are disposed between the upper end of the spring 20 and the lower end of the plug 24, whereby the top of the stem I4 at the upper end of said plunger.

The nozzle is opened by the pressure of the fuel on the conical portion ll of the plunger, which pressure forces the plunger upwardly against the pressure of the spring 2|. thereby lifting the valve element ll of said plunger of! its seat and permitting the fuel to escape through the annular discharge orifice It.

The lift or opening movement of the valve is fixed or limited by the annular abutment formed by the counterbored or enlarged outer'end portion I! of the bore It in the holder A, the stop shoulder l8 near the lower end of the spring thrust thimble l abutting again t u ment in the open position of the valve WhatI claim is:

wardly of the valve seat therein, a plunger reciprocable in said nozzle bore and having a valve element cooperating with the valveseat therein, a thimble axially slidable in the nozzle opposing end of the body bore, the inner end of said plunger extending into said thimble, and a spring in said holder bore for holding said thlm-.

vble ln abuttingrelatlon tosaid plunger and the tj valye elein ent of said plunger onsaidwalve seat,

1. A fuel injector comprising a holder having a bore opening through one end thereof, a nozzle secured to said end of said holderand'havin'g a bore therethrough'in register with the holder bore, the nozzle bore terminating at its outer end in a discharge orifice and having a. valve seat'therein inwardly of the latter, communicating-fuel supply passageways in said holder and nozzle opening into said nozzle bore inwardly of the valves'eat therein, a plunger reciprocable "in said nozzle bore and having a'valve element cooperating with the valve seat therein, a thimble axially slidable in the "nozzleop'posing end of the-body bore, the inner end of saidplunger extending into said thimble, and a spring in said holder bore'for holding said thimble in abutting relation to said plunger and the valve element of said plunger on said valve seat, said body time having an outwardly facing shoulder therein and said thimble having an external shoulder thereon adapted to-abut against said-first mentioned shoulder to thereby limit 'the inward movement offsaid plunger and'the'lift of the 'valve element v of the latter. e

2. A fuel injector comprising "aholderhaving a bore opening through oneend thereof, a nozzle secured to said end olfsa'id holder-and hav "ing "whore therethrough in"regis ter with the holder bore; the nozzle bore terminating at its outer end in'a discharge orifice and having a valve seattherein inwardly or the latter, com- I municatingfuelsupply passageways in said hold erfan'd lqzzle opening into said" nozzle borefinthe nozzle opposing end of said body bore being counterbored to form an outwardly facing annular shoulder therein, and said thimble having a collar, adapted to abut against said outwardly g facing shoulderofsaid body bore to thereby limit the. inward movement of said plunger and the lift of thelvalvelelernent thereof.

3. A'fu el injector comprising a holder having (a bore opening through one end thereof, a nozzle secured to said end of said holder and having a bore therethrough in register with the holder bore, the nozzle bore terminating at its outer end in a discharge orifice and having a valve seat therein inwardly of the latter," communicating fuel supply passageways in said holder and nozzle opening into said nozzle bore inwardly of the valve seat therein, a plunger reciprocable in said nozzle bore and having a valve element cooperating withthe' valve seat therein; a thimble axially slidable in the .nozzle opposing end of the body boreandhaving an axial recess in its-nozzle opposing'end,the inner end of said plunger having a stem .portion of reduced diameter extending into :the axial recess of said thimble, and a spring insaid holder bore for holding said thimble with the inner end of its axial recess in endwise abutting relation to the inner end of the stemnportion of said'plunger and the valve'element of 'said plunger onsaid valve seat, thenozzleopposingfend of said thimble having an externalnaunular rib thereon; and the nozzle-opposing end of said body bore being'counterbored to accommodate saidannularrib andto provide in said: body bore an annular-abutment for said annular'rib to thereby limit the-"inward "movementof; said plunger and the 'lift' of the valve elementthereoft.

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